Aerosol metering valve

ABSTRACT

A metering valve that includes a valve body defining a metering chamber having an inlet valve adapted to be reversibly actuable from an open position to a closed position located at the inlet, and an outlet valve adapted to be reversibly actuable from a dispensing to a non-dispensing position located at the outlet, where the outlet valve includes an outlet valve seat adapted to be in biasable contact with an outlet valve poppet is described. Aerosol containers and inhalation devices that include such metering valves are also described, as are methods of using such inhalation devices.

This invention relates to a metering valve for an aerosol container. Thevalve is particularly suitable for use in the metered dispensing ofmedicament by way of an inhalation device.

It is known to dispense medicament in aerosol form from a metered doseinhalation de vice. Such devices commonly comprise a housing andsupported therein, a container for the aerosol formulation. Thecontainer has a metering valve which generally is a slide or rotaryvalve. The slide or rotary valve comprises a valve stem which is movableagainst a restraining, generally frictional, force within a valve bodyfrom a dispensing position to a non-dispensing position.

In more detail, a slide valve typically comprises a valve body and within the valve body a sealing ring. A valve stem having a dispensingpassage therein is frictionally received by the sealing ring. The valvestem is slidably movable within the sealing ring from a valve-closedposition to a valve-open position in which the interior of the valvebody is in communication with the dispensing passage. An illustrativeslide valve is described in PCT application no. WO96/28367.

Actuation of a slide valve involves the application of sufficientmechanical force to overcome the frictional force between the valve stemand the sealing ring. In currently marketed inhalation devices themechanical force required to actuate the slide valve is generally of theorder of 20-40N. This force is often supplied by the patient manuallydepressing the container and valve body attached thereto relative to thehousing and valve stem supported thereby. The movement of the valve bodyrelative to the valve stem results in actuation of the valve and hencerelease of medicament.

With some current inhalation devices having a slide or rotary valve thevalve stem sometimes tends to stick, pause, or drag during the actuationcycle with the result that the patient can in some circumstancesperceive a resistance as the valve stem is moved. This may be partlycaused by medicament sedimenting or precipitating out of the aerosolformulation and depositing on the internal valve components, thepresence of medicament on the sliding interface increasing thefrictional force between the valve stem and the frictional seal. Varioussolutions to the problem of valve resistance have been suggestedincluding the use of lubricant on the valve stem and the seal.

It may be understood that effective delivery of medicament to thepatient using an inhalation device as described above is to an extentdependent on the patient's ability to coordinate the actuation of thedevice (e.g. firing of the aerosol) with the taking of a sufficientlystrong inward breath. The required coordination can present difficultiesto some patients, with the risk that these patients do not receive theappropriate dose of medicament. There have thus, been efforts to developinhalation devices which do not rely on manual actuation by the patient,in particular those which are actuable in response to the breath of apatient. These devices are often known as breath-actuable devices.

Breath-actuable devices typically comprise a source of stored energywhich on release actuates the slide valve of the medicament containerand hence releases medicament, and a breath trigger which triggers therelease of the stored energy in response to the breath of the patient.The stored energy source is required because the force required toactuate the slide valve (e.g. 20-40N as mentioned above) is too great tobe suppliable by the patients breath alone. Illustrative breath-actuabledevices are described in U.S. Pat. No. 5,655,523.

The applicants have now developed a metering valve which may be actuatedwithout any need for a dispensing stem or other dispensing member to bemoved relative to a valve body. Since the new valve requires no relativemovement of a valve stem to the valve body the problem of resistanceassociated with some slide and rotary valves is eliminated.

The newly developed metering valve is furthermore, operable by theapplication of a significantly lower force than is required to operate aconventional metering valve having a slide or rotary valve. The forcerequired can indeed, be so low that the valve is actuable by the forceof a patient's breath alone. The present metering valve is thus,particularly suitable for use in breath-activated devices. Such devicescan be much simpler than current breath-actuated devices because they donot necessarily require a source of stored energy.

EP-A-567,348 describes a metering valve for an aerosol container havinga two stage compress and release mechanism to fill the valve anddispense therefrom. The valve includes metering and dispensing membersconnected by a central bellows assembly or flexible membrane forrelative linear movement into and out of positive sealing engagementwith oppositely facing valve seats provided on a fixed valve housing andthe metering member respectively. The metering valve herein requires nosuch central bellows feature.

According to the present invention there is provided a metering valvefor an aerosol container comprising a valve body defining a meteringchamber, said metering chamber having an inlet and an outlet, said inletpermitting flow of aerosol from said container to the metering chamberand said outlet permitting dispensing of aerosol from the meteringchamber, the inlet having an inlet valve reversibly actuable from anopen to a closed position; and the outlet having an outlet valvereversibly actuable from a dispensing to a non-dispensing position,wherein said outlet valve comprises a outlet valve seat and an outletvalve poppet in biasable contact therewith.

As used herein the term valve poppet means any element which isreceivable by a valve seat to form a valve seal and which is movablefrom the valve seat to break the valve seal. The valve poppet can be ofessentially any suitable shape. The biasable contact between the outletvalve seat and outlet valve poppet may be provided by any suitablebiasing means, such as a spring.

The metering valve herein enables dispensing of aerosol contents withoutthe need for movement of a dispensing member relative to the valve body.In particular, the metering valve herein does not require the sliding orrotary movement of a valve stem relative to the valve body.

The metering valve herein is preferably designed to provide anon-convoluted flow passageway from the inlet to the outlet of themetering chamber.

Preferably, the metering valve forms a single integral unit which mayconveniently be fitted onto known aerosol containers for use in thedispensing of medicament.

Preferably, the inlet valve comprises an inlet valve seat and an inletvalve poppet in biasable contact therewith. The biasable contact may beprovided by any suitable biasing means (e.g. a spring).

Preferably, either one of the inlet and outlet valves is closed when themetering valve is in a rest position. More preferably both the inlet andoutlet valves are closed when the metering valve is at rest.

Preferably, the inlet and outlet valves are operable independently.Their operation may however, be coupled by using of a suitably coupledtrigger system.

In one aspect, any valve poppet comprises a hard, incompressiblematerial and any valve seat comprises a softer, compressible material.In another aspect, any valve poppet comprises a soft, compressiblematerial and any valve seat comprises a harder, incompressible material.

Alternatively, the inlet and outlet valve poppets and respective valveseats may both comprise hard, incompressible materials having smoothsurfaces to ensure good sealing.

Preferably, the valve additionally comprises an outlet valve mover formoving the outlet valve poppet out of contact with the outlet valveseat.

Preferably, the valve additionally comprises an inlet valve mover formoving the inlet valve poppet out of contact with the inlet valve seat.

In one aspect, either or both of said inlet valve mover or said outletvalve mover is mechanically actuable. That is to say, actuable byapplication of mechanical force either directly or through a mechanismcapable of transferring mechanical force.

In another aspect, either or both of the inlet valve mover or the outletvalve mover is electrically actuable. That is to say actuable byapplication of electrical current. More preferably, either or both ofthe inlet valve mover or the outlet valve mover comprises amulti-component strip or wire which is deformable in response toelectrical current flow.

Suitable multi-component strips typically comprise a plurality of layersof material, each material having a different coefficient of thermalexpansion. Preferred examples of multi-component strips include stripscomprising multiple layers of different metals (e.g. bimetallic strips)and strips comprising at least one piezoelectric or piezoresistivematerial. Suitable piezoelectric materials include piezoelectricceramics, such as compounds of lead zirconate and lead titonate, andpiezoelectric crystals which are generally polycrystalline ferroelectricmaterials with the perovskite structure.

Suitable multi-component wires comprise an alloy which undergoes a phasetransition on heating which results in contraction thereof. Typicallythe degree of contraction is from 2% to 8%. Such alloys are generallyknown as shape memory alloys. Certain shape memory alloys also undergo achange in shape on recooling. Such two way shape memory alloys are alsoenvisaged for use herein.

In one embodiment, the alloy is preferably a nickel-titanium alloy suchas a nickel-titanium alloy comprising from 5% to 95%, preferably from20% to 80%, nickel by weight and from 95% to 5%, preferably from 80% to20%, titanium by weight. By nickel-titanium alloy it is meant an alloycomprised essentially of nickel and titanium, although other elementsmay be present in small (e.g. trace) amounts.

In other embodiments, the alloy is preferably a copper-aluminium-nickelalloy or a copper-zinc-aluminium alloy. Trace amounts of other elementsmay also be present.

Suitable wires typically have a diameter from 30 to 400 micrometers,preferably from 50 to 150 micrometers.

Preferably, either or both of the inlet valve mover or the outlet valvemover is magnetically actuable.

Preferably, either or both of the inlet valve mover or the outlet valvemover compresses magnetic material or material which is magneticallyinductive, that is to say material into which magnetism can be induced.The material may be permanently or non-permanently magnetisable.

Preferably, either or both of the inlet valve mover or the outlet valvemover is pneumatically actuable.

Preferably, either or both of the inlet valve mover or the outlet valvemover is hydraulically actuable. More preferably, either or both of theinlet valve mover or the outlet valve mover comprises means, such as afluid-filled bag or tube capable of transferring hydraulic force.

Preferably, the outlet valve poppet and/or the inlet valve poppetcomprises an element in the form of a ball, a mushroom, a cone, a discor a plug.

Preferably, the valve body additionally defines a sampling chamber andthe inlet permits flow from the sampling chamber to the meteringchamber.

The metering chamber is preferably shaped to minimise the surfacecontact area with the aerosol and thereby reduce deposition ofmedicament thereon.

In one aspect, the metering chamber has a fixed volume.

In another aspect, the metering chamber is of variable volume. Thevolume of the metering chamber may for example be varied to provide theoptimum amount of medicament for release. In one preferred aspect, thevolume of the metering chamber is variable automatically in response toa dosing signal sent from an electronic information process or.

Various types of variable volume metering chambers are envisaged.Suitable chambers comprise a fixed volume chamber whose metering volumeis variable by insertion of a plunger or piston. The piston or plungermay have fixed form or alternatively may comprises an element ofvariable shape and volume such as an inflatable balloon. Other suitablechambers comprise a chamber which is expandable because it is formedfrom a flexible/expandable material. Further suitable chambers havetelescopic or concertina arrangements to allow for mechanical expansionof the metering volume.

According to another aspect of the present invention there is providedan aerosol container comprising a metering valve as described above.

In a preferred aspect the valve body of the metering valve is notmovable relative to the container. Also, the metering valve contains nomovable stem. This contrasts with current slide valves where actuationof the valve is achievable by relative movement of the aerosol containerto the valve stem.

In one aspect, the aerosol container comprises a suspension of amedicament in a propellant. More preferably, the propellant is liquefiedHFA134a, HFA-227 or carbon dioxide. More preferably, the medicament isselected from the group consisting of albuterol, salmeterol, fluticasonepropionate, beclomethasone dipropionate, salts or solvates thereof andany mixtures thereof.

In another aspect, the aerosol container comprises a compressed gas,preferably compressed air.

According to a further aspect of the present invention there is providedan inhalation device for dispensing medicament to a patient comprising ahousing; an aerosol container, locatable within said housing, saidaerosol container comprising a metering valve as described above; and anoutlet valve trigger for triggering the movement of the outlet valvepoppet out of contact with the outlet valve seat.

When the aerosol container comprises an inlet poppet valve theinhalation device preferably also comprises an inlet valve trigger fortriggering the movement of the inlet valve poppet out of contact withthe inlet valve seat.

Preferably, either or both of said outlet valve trigger or said inletvalve trigger is triggerable in response to the breath of a patient. Theoutlet valve or inlet valve triggers may be triggerable in response tothe inward breath of the patient, or alternatively triggerable at atrigger point which is coupled to the end of the exhalation part of thepatient's breath cycle. Inhalation devices which are triggerable at theend of the exhalation part of the breath cycle are described in UKpatent application no. 9905134.4.

Preferably, either or both of the outlet valve trigger or the inletvalve trigger communicates with a sensor which senses the breath of apatient.

In one aspect, the sensor comprises a breath-movable element which ismovable in response to the breath of a patient. Preferably, thebreath-movable element is selected from the group consisting of a vane,a sail, a piston and an impeller.

In another aspect, the sensor comprises a pressure sensor for sensingthe pressure profile associated with the breath of a patient.

In a further aspect, the sensor comprises an airflow sensor for sensingthe airflow profile associated with the breath of a patient.

In a further aspect, the sensor comprises a temperature sensor forsensing the temperature profile associated with the breath of a patient.

In a further aspect, the sensor comprises a moisture sensor for sensingthe moisture profile associated with the breath of a patient.

In a further aspect, the sensor comprises a gas sensor for sensing theoxygen or carbon dioxide profile associated with the breath of apatient.

In a further aspect, the sensor comprises a piezoelectric orpiezoresistive element.

The outlet valve trigger and the inlet valve trigger may beindependently triggerable or they may be triggerable in a coupledfashion.

Preferably, either or both of the outlet valve trigger or the inletvalve trigger is a mechanical trigger. In one aspect, the mechanicaltrigger comprises a lever mechanism. In another aspect, the mechanicaltrigger comprises a torque 110 transfer mechanism.

Preferably, either or both of the outlet valve trigger or the inletvalve trigger comprises comprises a multi-component strip which isdeformable in response to electrical current flow. The multi-componentstrip typically comprises a plurality of layers of material, eachmaterial having a different coefficient of thermal expansion. Preferredexamples of multi-component strips include strips comprising multiplelayers of different metals (e.g. bimetallic strips) and stripscomprising at least one piezoelectric or piezoresistive material.

Preferably, either or both of the outlet valve trigger or the inletvalve trigger is a magnetic trigger.

In one aspect, the outlet valve trigger interacts magnetically with theoutlet valve poppet and/or the inlet valve trigger interactsmagnetically with the inlet valve poppet.

In another aspect, the outlet valve trigger interacts magnetically witha outlet shuttle contacting the outlet valve poppet and/or the inletvalve trigger interacts magnetically with an inlet shuttle contactingthe inlet valve poppet. Preferably, the outlet shuttle and/or inletshuttle comprises magnetic material.

In a further aspect, the outlet shuttle comprises material which ismagnetically inductive and the outlet valve trigger comprises aninductive element capable of inducing magnetism therein and/or the inletshuttle comprises material which is magnetically inductive and the inletvalve trigger comprises an inductive element capable of inducingmagnetism therein.

Preferably, either or both of the outlet valve trigger or the inletvalve trigger is a pneumatic trigger.

Preferably, either or both of the outlet valve trigger or the inletvalve trigger is a hydraulic trigger. More preferably, the hydraulictrigger comprises a fluid-filled bag or tube capable of transferringhydraulic force.

The invention will now be described further with reference to theaccompanying drawing in which:

FIG. 1 is a sectional view of a first metering valve in accord with thepresent invention;

FIG. 2 is a sectional view of a second metering valve in accord with thepresent invention;

FIG. 3 is a sectional view of a third metering valve in accord with thepresent invention;

FIG. 4 is a sectional view of a fourth metering valve in accord with thepresent invention;

FIG. 5 a is a sectional view of a fifth metering valve in accord withthe present invention;

FIG. 5 b is a sectional view of a detail of the valve of FIG. 5 a;

FIG. 6 is a sectional view of a sixth metering valve in accord with thepresent invention;

FIG. 7 is a plan view of the valve actuation mechanism of a seventhmetering valve in accord with the present invention;

FIGS. 8 a to 8 d show various forms of poppet valve suitable for use inaccord with the invention;

FIG. 9 is a sectional view of an eighth metering valve in accord withthe invention.

FIG. 10 is a sectional view of a ninth metering valve in accord with theinvention;

FIG. 11 is a sectional view of a tenth metering valve in accord with theinvention;

FIG. 12 is a sectional view of an eleventh metering valve in accord withthe invention;

FIG. 13 is a sectional view of a twelfth metering valve in accord withthe invention;

FIG. 14 is a sectional view of a thirteenth metering valve in accordwith the invention; and

FIG. 15 is a schematic view of an inhalation device in accord with thepresent invention.

FIG. 1 shows an aerosol metering valve herein. The valve comprises avalve body 10 which defines a metering chamber 12 and a sampling chamber14. The metering chamber 12 has an inlet 20 permitting flow of aerosolfrom the sampling chamber 14 which in turn receives aerosol from acontainer (not shown) and an outlet 30 permitting dispensing of aerosolfrom the metering chamber 12. The inlet 20 is provided with valve meanscomprising a valve seat 22 and a valve poppet in the form of a metalball 24. The metal ball 24 is biased towards the valve seat 22 by theaction of spring 26. The outlet 30 is also provided with valve meanscomprising a valve poppet in the form of a metal ball 34 held by aspring 36 in biased contact with a valve seat 32. The valve body 10 iswithin a housing 6 shaped such as to define a circular track 8 runningupwardly in parallel with the exterior of the valve body 10. Within thetrack 8 is contained a magnetic ring 40 which is movable up and down thetrack 8.

Actuation of the valve of FIG. 1 is achievable by movement of themagnetic ring 40 which can magnetically interact with the metal ballpoppets 24,34 to dislodge them from their seats 22, 32. Movement ofmagnetic ring itself is for example, achievable by use of a secondmagnet (not shown). In a typical operation the inlet 20 valve will firstbe opened to allow metered flow of aerosol from the sampling chamber 14into the metering chamber 12. The outlet 30 valve is then opened toallow for dispensing of the aerosol.

FIG. 2 shows an aerosol metering valve herein. The valve comprises avalve body 110 which defines a metering chamber 112 and a samplingchamber 114. The metering chamber has an inlet 120 permitting flow ofaerosol from the sampling chamber 114 and an outlet 130 permittingdispensing of aerosol from the metering chamber 112. The inlet 120 isprovided with valve means comprising a valve seat 122 and a valve poppetin the form of a resilient ball 124. The ball 124 is biased towards thevalve seat 122 by the action of spring 126. The outlet 130 is alsoprovided with valve means comprising a valve poppet in the form of aball 134 biased into contact with a valve seat 132 by action of spring136. The valve body 110 is within housing 106 and the housing isprovided with fixing screws 105, 107 for fixing the valve to an aerosolcontainer (not shown). Movable magnetic rings 140, 142 contact theresilient balls 124, 134 of the inlet 120 and outlet 130 valvesrespectively. The magnetic rings 140, 142 are in turn in magneticcommunication with shuttle magnets 150 and 152.

Actuation of the metering valve of FIG. 2 is achievable by movement ofthe magnetic rings 140, 142 to physically dislodge the resilient balls124, 134 from their respective seats 122, 132. Movement of magneticrings is achievable by movement of the shuttle magnets 150, 152. Theshuttle magnets 150, 152 may, in turn be coupled to a mechanical triggersuch as a lever mechanism (not shown). In a typical operation the inlet120 valve will first be opened to allow metered flow of aerosol from thesampling chamber 114 into the metering chamber 112. The outlet 130 valveis then opened to allow for dispensing of the aerosol.

FIG. 3 shows an aerosol metering valve herein. The valve comprises avalve body 210 which defines a metering chamber 212. The meteringchamber has an inlet 220 permitting flow of aerosol from a container(not shown) and an outlet 230 permitting dispensing of aerosol from themetering chamber 212. The inlet 220 is provided with valve meanscomprising a valve seat 222 and a valve poppet in the form of aresilient plastic ball 224. The ball 224 is biased towards the valveseat 222 by the action of spring 226. The outlet 230 is also providedwith valve means comprising a valve poppet in the form of a resilientplastic ball 234 biased into contact with a valve seat 232 by action ofspring 236. The valve body 210 is within a housing 206. The housing 206shaped is such as to define two circular cavities 208, 209, each runningupwardly in parallel with a portion of the exterior of the valve body210 and respectively positioned around the inlet 220 and outlet 230valves. First and second circular solenoid cores 240, 242 are movablylocated within the first and second circular cavities 208, 209 andrespectively engage the inlet and outlet ball valves 224, 234. Thecircular solenoid cores 240, 242 are in turn, positioned for inductivecommunication with outer solenoid coil windings magnets 250 and 252. Thesolenoid coil windings 250, 252 are connected to an electrical powersource (not shown).

Actuation of the metering valve of FIG. 3 is achievable by movement ofthe circular solenoid cores 240, 242 to physically dislodge theresilient balls 224, 234 in an upward direction from their respectiveseats 222, 232. Movement of the circular solenoid cores 240, 242 is inturn achievable by the application of electrical current to the solenoidcoil windings 250, 252. In a typical operation the inlet 220 valve willfirst be opened to allow metered flow of aerosol into the meteringchamber 212. The outlet 230 valve is then opened to allow for dispensingof the aerosol.

FIG. 4 shows an aerosol metering valve herein. The valve comprises avalve body 310 which defines a metering chamber 312 and a samplingchamber 314. The metering chamber 312 has an inlet 320 permitting flowof aerosol from the sampling chamber 314 and an outlet 330 permittingdispensing of aerosol from the metering chamber 312. The inlet 320 isprovided with valve means comprising a valve seat 322 and a valve poppetin the form of a resilient ball 324. The ball 324 is biased towards thevalve seat 322 by the action of spring 326. The outlet 330 is alsoprovided with valve means comprising a valve poppet in the form of aresilient ball 334 biased into contact with a valve seat 332 by actionof spring 336. Gripping arms 340, 342 grip the resilient balls 324, 334of the inlet 320 and outlet 330 valves respectively. The gripping armsare formed from a bimetallic strip wherein each of the bimetalliccomponents thereof has a different coefficient of thermal expansion. Thegripping arms 340, 342 are connectable to an electrical power source(not shown).

Actuation of the metering valve of FIG. 4 is achievable by movement ofthe gripping arms 340, 342 to physically dislodge the resilient balls324, 334 from their respective seats 322, 332. Movement of the grippingarms 340, 342 is in turn achievable by the application of electricalcurrent which causes deformation of the bimetallic strip from which thearms 340, 342 are formed. In a typical operation the inlet 320 valvewill first be opened to allow metered flow of aerosol into the meteringchamber 312. The outlet 330 valve is then opened to allow for dispensingof the aerosol.

FIG. 5 a shows an aerosol metering valve herein and FIG. 5 b shows adetail of this valve when the inlet valve is in the open position. Themetering valve comprises a valve body 410 which defines a meteringchamber 412 and a sampling chamber 414. The metering chamber has aninlet 420 permitting flow of aerosol from the sampling chamber 414 andan outlet 430 permitting dispensing of aerosol from the metering chamber412. The inlet 420 is provided with valve means comprising a valve seat422 and a valve poppet in the form of a resilient ball 424. The ball 424is biased towards the valve seat 422 by the action of spring 426. Theoutlet 430 is also provided with valve means comprising a valve poppetin the form of a resilient ball 434 biased into contact with a valveseat 432 by action of spring 436. Shaped, flexible elastomer bags 440,442 sit within and on both sides of access holes 416,418 provided in thesampling chamber 414 and metering chamber 412 respectively. Theelastomer bags 440, 442 contain fluid material. It may be seen that oneportion of each of the elastomer bags 440, 442 contacts the resilientballs 424, 434 of the inlet 420 and outlet 430 valves respectively. Itmay also be seen that another portion of each of the elastomer bags 440,442 contacts an impacting arm 450 which is pivoted at pivot 454. Theimpacting arm 450 is itself connected to handle 456 which may itself beattached to a breath-actuable vane (not shown).

Actuation of the metering valve of FIGS. 5 a and 5 b is achievable byimpacting the flexible, fluid-filled elastomer bags 440, 442 tophysically dislodge the resilient balls 424,434 from their respectiveseats 422, 432. Impaction of the elastomer bags 440, 442 is in turnachievable by the impacting movement of the impacting arm 450. The bags440, 442 are shaped such as to deform upon impact to allow for transferof the energy of impaction through the fluid contents.

The deformation of one of the bags 440 on being struck by the impactingarm 450 is shown in FIG. 5 b which also shows the dislodgement of theresilient ball 424 from its seat 422. In a typical operation the inlet420 valve will first be opened to allow metered flow of aerosol into themetering chamber 412. The outlet 430 valve is then opened to allow fordispensing of the aerosol. It will be appreciated that the illustratedpivotal mounting 454 of the impacting arm 450 only allows for impactionof one of the elastomer bags 440,442, and hence opening of only one ofthe inlet 420 or outlet 430 valves, at a time.

FIG. 6 shows an aerosol metering valve herein. The valve comprises avalve body 510 which defines a metering chamber 512 and a samplingchamber 514. The metering chamber has an inlet 520 permitting flow ofaerosol from the sampling chamber 514 and an outlet 530 permittingdispensing of aerosol from the metering chamber 512. The inlet 520 isprovided with valve means comprising a valve seat 522 and a valve poppetin the form of a resilient ball 524. The ball 524 is biased towards thevalve seat 522 by the action of spring 526. The outlet 530 is alsoprovided with valve means comprising a valve poppet in the form of aball 534 biased into contact with a valve seat 532 by action of spring536. The valve body 510 is within a housing 506 and the housing isprovided with fixing screws 505, 507 for fixing the valve to an aerosolcontainer 503 (shown in part only). Shaped pins 540, 542 sit within andon both sides of access holes 516, 518 provided in the sampling chamber514 and metering chamber 512 respectively. It may be seen that the tailend of each of the shaped pins 540, 542 contacts the resilient balls524, 534 of the inlet 520 and outlet 530 valves respectively. It mayalso be seen that the head of each of the pins 540, 542 contacts anelastomer diaphragm 546,548 which in turn contacts double-headedtransfer pins 550, 552. The elastomer diaphragms 546,548 and thetransfer pins 550, 552 are mounted in side compartments of the valvebody. The outer heads of the transfer pins 550, 552 are impactable by animpacting arm 560 which is pivoted at pivot 564. The impacting arm 560may itself be connected to a breath-actuable vane (not shown).

Actuation of the metering valve of FIG. 6 is achievable by movement ofthe shaped pins 540, 542 to physically dislodge the resilient balls 524,534 from their respective seats 522, 532. Movement of the shaped pins540, 542 is in turn achievable by impacting the elastomer diaphragms546, 548 with their respective transfer pins 550, 552 following animpact by the impacting arm 560. In a typical operation the inlet 520valve will first be opened to allow metered flow of aerosol into themetering chamber 512. The outlet 530 valve is then opened to allow fordispensing of the aerosol. It will be appreciated that the illustratedpivotal mounting 564 of the impacting arm 560 only allows for impactionof one of the transfer pins 550,552, and hence opening of only one ofthe inlet 520 or outlet 530 valves, at a time.

FIG. 7 shows a simplified, schematic representation of a poppet valveactuation mechanism suitable for use in an aerosol metering valveherein. The metering valve might, for example be of a type similar tothose shown in FIGS. 1 to 6 but including the poppet valve actuationmechanism now described. The portion of the valve body 610 which definesa metering chamber 612 is shown. The metering chamber has an outlet 630permitting dispensing of aerosol from the metering chamber 612. Theoutlet 630 is provided with valve means comprising a valve poppet in theform of a resilient ball 634 biased into contact with a valve seat 632by action of spring 636. An actuator rod 642 sits within and on bothsides of an access hole 618 provided in the metering chamber 612. Thetail end of the actuator rod 642 contacts the resilient ball 634 of theoutlet 630 valve. The shaft of the actuator rod 642 is housed withintorque tube 652 and a handle 656 is provided to the head of the actuatorrod 642.

Actuation of the valve of FIG. 7 is achievable by rotating the actuatorrod 642 such that its tail end physically dislodges the resilient ball634 from its seat 622. The actuator rod 642 is rotated by use of thehandle 656 at its head. The handle 656 may be coupled to any suitabledrive means including mechanical and electrical drive means (not shown).

FIGS. 8 a to 8 d show various forms of poppet valve suitable for use inaccord with the invention. These employ valve poppets having differentforms. These alternative valve poppets may be used in the meteringvalves of FIGS. 1 to 6 or the poppet valve actuation mechanism of FIG. 7instead of the ball valve poppets shown therein.

In more detail, FIGS. 8 a to 8 d show a valve body 710 a-d supporting avalve 1 seat 732 a-d and a valve poppet 734 a-d which sits on valve seat732 a-d. In FIG. 8 a the valve poppet 734 a is in the form of amushroom. In FIG. 8 b the valve poppet 734 b is in the form of a cone.In FIG. 8 c the valve poppet 734 c is in the form of a disc. In FIG. 8 dthe valve poppet 734 d is in the form of a plug.

FIG. 9 shows an aerosol metering valve herein in the rest position. Thevalve comprises a valve body 810 which defines a metering chamber 812and a sampling chamber 814. The metering chamber has an inlet 820permitting flow of aerosol from the sampling chamber 814 and an outlet830 permitting dispensing of aerosol from the metering chamber 812. Theinlet 820 is provided with valve means comprising a valve seat 822 and avalve poppet in the form of a first shaped magnet 824 which has aflexible seal 823 provided thereto. The seal 823 is biased away from thevalve seat 822 by the repulsive action of toroidal magnet 850. Theoutlet 830 is also provided with valve means comprising a valve poppetin the form of a second shaped magnet 834 having a flexible seal 833biased into contact with a valve seat 832 by the attractive action oftoroidal magnet 850. Both shaped magnets 824, 834 are chamfered toprovide flow passageways therethrough.

Actuation of the metering valve of FIG. 9 is achievable by movement ofthe toroidal magnet 850 downwards which removes the repulsive force fromthe first shaped magnet 824 which may therefore contact the valve seat822 closing the inlet 820. Simultaneously, the toroidal magnet 850attracts the second shaped magnet 834 which moves off its seat 832thereby opening the outlet 830. The toroidal magnet 850 may in turn becoupled to a mechanical trigger such as a lever mechanism (not shown).

FIG. 10 shows an aerosol metering valve herein. The metering valvecomprises a valve body 910 which defines a metering chamber 912 and asampling chamber 914. The sampling chamber 914 is funnel-shaped toencourage ready flow of aerosol from the container to the meteringchamber 912. The metering chamber 912 has an inlet 920 permitting flowof aerosol from the sampling chamber 914 and an outlet 930 permittingdispensing of aerosol from the metering chamber 912. The inlet 920 isprovided with valve means comprising a valve seat 922 and a valve poppetin the form of a resilient ball 924. The ball 924 is biased towards thevalve seat 922 by the action of spring 926. The outlet 930 is alsoprovided with valve means comprising a valve poppet in the form of aresilient ball 934 biased into contact with a valve seat 932 by actionof spring 936. The valve body 910 is provided with fixing screws 905,907 for fixing the valve to an aerosol container 903 (shown in partonly). Shaped pins 940, 942 sit within and on both sides of access holes916, 918 provided in the sampling chamber 914 and metering chamber 912respectively. It may be seen that the tail end of each of the shapedpins 940, 942 contacts the resilient balls 924, 934 of the inlet 920 andoutlet 930 valves respectively. It may also be seen that each of thepins 940, 942 is biased to a rest position by spring 944, 946 away fromthe respective resilient ball 924, 934. The outer heads of the transferpins 941, 943 are shaped for impact. A suitable impactor (not shown)might for example, comprise an impacting arm as shown in FIG. 6 whichmay itself be connected to a breath-actuable vane.

Actuation of the metering valve of FIG. 10 is achievable by impactingthe heads 941, 943 of the shaped pins 940, 942 to physically dislodgethe resilient balls 924, 934 from their respective seats 922, 932. Theaction of the springs 944, 946 will return each pin to the rest positionon removal of the impacting force. In a typical operation the inlet 920valve will first be opened to allow metered flow of aerosol into themetering chamber 912. The outlet 930 valve is then opened to allow fordispensing of the aerosol. The impactor may be configured to allow forimpaction of one of the shaped pins 940, 942, and hence opening of onlyone of the inlet 920 or outlet 930 valves, at a time.

FIG. 11 shows an aerosol metering valve herein. The metering valvecomprises a valve body 1010 which defines a metering chamber 1012 and asampling chamber 1014. The metering chamber 1012 has an inlet 1020permitting flow of aerosol from the sampling chamber 1014 and an outlet1030 permitting dispensing of aerosol from the metering chamber 1012.The inlet 1020 is provided with valve means comprising a valve seat 1022and a valve poppet in the form of a cone 1024. The cone 1024 is biasedtowards the valve seat 1022 by the action of spring 1026 (restposition). The outlet 1030 is also provided with valve means comprisinga valve poppet in the form of a cone 1034 biased into contact with avalve seat 1032 by action of spring 1036 (rest position). Shapedactuator pins 1040, 1042 sit within and on both sides of access passages1016, 1018 provided in the valve body 1010. It may be seen that the tailend of each of the actuator pins 1040, 1042 connects with the conepoppets 1024, 1034 of the inlet 1020 and outlet 1030 valvesrespectively. It may also be seen that the tail end each of the pins1040, 1042 is provided with protective bellow seals 1046, 1048 whichprovide a seal between the cone poppets 1024, 1034 and the actuator pins1040, 1042. The outer heads of the transfer pins 1041, 1043 are shapedfor impact. A suitable impactor (not shown) might for example, comprisean impacting arm as shown in FIG. 6 which may itself be connected to abreath-actuable vane.

Actuation of the metering valve of FIG. 11 is achievable by impactingthe heads 1041, 1043 of the actuator pins 1040, 1042 to physicallydislodge the cone poppets 1024, 1034 from their respective seats 1022,1032. The action of the springs 1026, 1036 will return each pin 1040,1042 to the rest position on removal of the impacting force. In atypical operation the inlet 1020 valve will first be opened to allowmetered flow of aerosol into the metering chamber 1012. The outlet 1030valve is then opened to allow for dispensing of the aerosol. Theimpactor may be configured to allow for impaction of one of the actuatorpins 1040, 1042, and hence opening of only one of the inlet 1020 oroutlet 1030 valves, at a time.

FIG. 12 shows an aerosol metering valve and aerosol container (in part)herein. The valve comprises a valve body 1110 which defines a meteringchamber 1112 and a sampling chamber 1114. The sampling chamber 1114 hasinlets 1116, 1117 permitting flow of aerosol from the aerosol container1105. The metering chamber 1112 has an inlet 1120 permitting flow ofaerosol from the sampling chamber 1114 and an outlet 1130 permittingdispensing of aerosol from the metering chamber 1112. The inlet 1120 isprovided with valve means comprising a valve seat 1122 and a valvepoppet in the form of a sliding piston 1124 with poppet head 1125. Thepoppet head 1125 of the sliding piston 1124 is biased towards the valveseat 1122 by the action of spring 1126. The outlet 1130 is also providedwith valve means comprising a valve poppet in the form of a slidingpiston 1134 with poppet head 1135 biased into contact with a valve seat1132 by action of spring 1136. It may be seen that the bodies of slidingpistons 1124 and 1134, and their respective biasing springs 1126 and1136, are respectively enclosed in hermetically sealed piston shafts1128 and 1138. The ball-shaped 1125, 1135 poppet heads of the slidingpistons 1124, 1134 however, protrude from the piston shafts to contactthe respective valve seats 1122, 1132. Shape memory alloy wires 1140;1142 are fixed to the sliding pistons 1124, 1134 of the inlet 1120 andoutlet 1130 valves respectively. The wires 1140, 1142 are also fixed toanchor points 1146, 1148 at the top of each respective piston shaft1128, 1138. The wires 1140, 1142 are formed from a nickel/titanium alloywhich contracts on heating, for example in response to electricalcurrent flow. The wires 1140, 1142 are each connected to an electricalpower source 1150, 1152.

Actuation of the metering valve of FIG. 12 is achievable by contractionof the shape memory alloy wires 1140, 1142 to move the sliding pistons1124, 1134 within their respective shafts 1128, 1138 and hence to movethe poppet heads 1125, 1135 from their respective seats 1122, 1132.Contraction of the wires 1140, 1142 is in turn achievable by the flow ofelectrical current through the wires 1140, 1142. In a typical operationthe inlet 1120 valve will first be opened to allow metered flow ofaerosol into the metering chamber 1112. The outlet 1130 valve is thenopened to allow for dispensing of the aerosol.

FIG. 13 shows an aerosol metering valve herein which is a variation ofthe metering valve of FIG. 9. The valve comprises a valve body 1210which defines a metering chamber 1212 and a sampling chamber 1214. Thevalve body 1210 is provided with fixing holes 1205, 1207 forscrew-fixing the valve to an aerosol container (not shown). The meteringchamber has an inlet 1220 permitting flow of aerosol from the samplingchamber 1214 and an outlet 1230 permitting dispensing of aerosol fromthe metering chamber 1212. The inlet 1220 has a bore which is narrow forease of aerosol flow, typically being approximately 2 mm in diameter.The inlet 1220 is provided with valve means comprising a valve seat 1222and a valve poppet in the form of a first shaped magnet 1224 which has aflexible ball head 1223 provided thereto. As shown, the magnet 1224 isbiased away from the valve seat 1222 by the repulsive action of toroidalmagnet 1250. When so biased away from the valve seat 1222, the magnet1224 may move to position 1224 a in which it abuts inclined surface 1209at the mouth of the sampling chamber 1214 thereby permitting goodaerosol flow to the inlet 1220 of the metering chamber 1212. Thesampling chamber 1214 is also provided with slots 1215 a, 1215 b tofurther assist aerosol flow. The outlet 1230 has valve means comprisinga valve poppet in the form of a second shaped magnet 1234 having aflexible ball head 1233 in contact with valve seat 1232. The meteringchamber 1212 is provided with slots 1213 a, 1213 b to further assistaerosol flow. Both shaped magnets 1224, 1234 are chamfered to provideflow passageways therethrough.

Actuation of the metering valve of FIG. 13 is achievable by movement ofthe toroidal magnet 1250 downwards which removes the repulsive forcefrom the first shaped magnet 1224 which may therefore contact the valveseat 1222 closing the inlet 1220. Simultaneously, the toroidal magnet1250 attracts the second shaped magnet 1234 which moves off its seat1232 thereby opening the outlet 1230. The toroidal magnet 1250 may inturn be coupled to a mechanical trigger such as a lever mechanism (notshown).

FIG. 14 shows an aerosol metering valve herein. The metering valvecomprises a valve body 1310 which defines a metering chamber 1312 and asampling chamber 1314. The valve body 1310 is provided with fixingscrews 1305, 1307 for fixing the valve to an aerosol container (notshown).

The sampling chamber 1314 is funnel-shaped to encourage ready flow ofaerosol from the container to the metering chamber 1312. The meteringchamber 1312 has an inlet 1320 permitting flow of aerosol from thesampling chamber 1314 and an outlet 1330 permitting dispensing ofaerosol from the metering chamber 1312. The inlet 1320 is provided withvalve means comprising a valve seat 1322 in the form of a rubber o-ringand a valve poppet in the form of a resilient ball 1324. The outlet 1330is also provided with valve means comprising a valve poppet in the formof a resilient ball 1334 contacting valve seat 1332. Actuator rods 1340,1350 are snugly received by cavities in the resilient balls 1324, 1334of the respective inlet and outlet valve poppets. The actuator rods1340, 1350 also thread through resilient ball seals 1342, 1352 which sitwithin o-rings 1344, 1354 to form pivot seals. It may be appreciatedthat the ball poppets 1324, 1334 are movable by a pivoting (i.e. seesaw)movement of their respective actuator rods 1340, 1350 within therespective pivot seals. The ends 1346, 1356 of the actuator rods 1340,1350 are biased by the action of torsion springs 1348, 1358 which act onthe rods 1340, 1350 such that the poppet seals 1324, 1334 are biased tothe closed position. The springs 1348, 1358 are attached to arms 1360,1362 which protrude from the upper part of the valve body 1310. Stops1364, 1366 are provided to prevent excessive movement of the actuatorrods 1340, 1350 in the vertical (i.e. up/down) direction. The actuatorrods 1340, 1350 may be connected to suitable breath-actuable vanes (notshown) to enable breath-actuation thereof.

Actuation of the metering valve of FIG. 14 is achievable by pivoting theactuator rods 1340, 1350 to dislodge the resilient balls 1324, 1334 fromtheir respective seats 1322, 1332. The action of the springs 1348, 1358will return each rod 1340, 1350 and associated ball poppet 1324, 1334 tothe rest position on removal of the pivoting force. In a typicaloperation the inlet 1320 valve will first be opened to allow meteredflow of aerosol into the metering chamber 1312. The outlet 1330 valve isthen opened to allow for dispensing of the aerosol. The valve operationwill typically be configured to allow for pivoting of one of theactuator rods 1340, 1350 and hence opening of only one of the inlet 1320or outlet 1330 valves, at a time.

FIG. 15 shows a schematic representation of an inhalation device herein.The device comprises a housing 1460 including a mouthpiece 1462 andshaped for receipt of an aerosol container 1470. The aerosol container1470 has a metering valve 1472 which may be any metering valve describedherein. Within the aerosol container 1470 is provided stirrer 1471 forassisting in the agitation of the aerosol contents thereof prior todispensing. The metering valve 1472 has a valve stem 1474 including avalve nozzle 1476 for dispensing aerosol 1478 therefrom. The meteringvalve 1472 connects with valve driver system 1480 which may comprise anyof the valve driver or trigger elements described herein. The valvedriver system 1480 in turn communicates with breath sensor system 1490which may comprise any breath sensing mechanism described herein. Dosecounter 1492 is provided to count the number of actuations of the valve1472 and may be connected to a display (not shown) to display dosesdispensed or doses remaining in the container 1470.

It may be appreciated that any of the parts of the metering valve whichcontact the medicament suspension may be coated with materials such asfluoropolymer materials which reduce the tendency of medicament toadhere thereto. Suitable fluoropolymers include polytetrafluoroethylene(PTFE) and fluoroethylene propylene (FEP). Any movable parts may alsohave coatings applied thereto which enhance their desired movementcharacteristics. Frictional coatings may therefore be applied to enhancefrictional contact and lubricants used to reduce frictional contact asnecessary.

The aerosol container and valve of the invention is suitable fordispensing medicament, particularly for the treatment of respiratorydisorders such as asthma and chronic obstructive pulmonary disease(COPD).

Appropriate medicaments may thus be selected from, for example,analgesics, e.g., codeine, dihydromorphine, ergotamine, fentanyl ormorphine; anginal preparations, e.g., diltiazem: antiallergics, e.g.,cromoglycate, ketotifen or nedocromil; antiinfectives e.g.,cephalosporins, penicillins, streptomycin, sulphonamides, tetracydinesand pentamidine; antihistamines, e.g., methapyrilene;anti-inflammatories, e.g., beclomethasone dipropionate, fluticasonepropionate, flunisolide, budesonide, rofleponide, mometasone furoate ortriamcinolone acetonide; antitussives, e.g., noscapine; bronchodilators,e.g., albuterol, salmeterol, ephedrine, adrenaline, fenoterol,formoterol, isoprenaline, metaproterenol, phenylephrine,phenylpropanolamine, pirbuterol, reproterol, rimiterol, terbutaline,isoetharine, tulobuterol, or(-)-4-amino-3,5-dichloro-α[[[6[2-(2-pyridinyl)ethoxy]hexyl]methyl]benzenemethanol; diuretics, e.g., amiloride; antcholinergics, e.g.,ipratropium, tiotropium, atropine or oxitropium; hormones, e.g.,cortisone, hydrocortisone or prednisofone; xanthines, e.g.,aminophylline, choline theophyllinate, lysine theophyllinate ortheophylline; therapeutic proteins and peptides, e.g., insulin orglucagon. It will be clear to a person skilled in the art that, whereappropriate, the medicaments may be used in the form of salts, (e.g., asalkali metal or amine salts or as acid addition salts) or as esters(e.g., lower alkyl esters) or as solvates (e.g., hydrates) to optimisethe activity and/or stability of the medicament.

Preferred medicaments are selected from albuterol, salmeterol,fluticasone propionate and beclomethasone dipropionate and salts orsolvates thereof, e.g., the sulphate of albuterol and the xinafoate ofsalmeterol.

Medicaments can also be delivered in combinations. Preferredformulations containing combinations of active ingredients containsalbutamol (e.g., as the free base or the sulphate salt) or salmeterol(e.g., as the xinafoate salt) in combination with an antiinflammatorysteroid such as a beclomethasone ester (e.g., the dipropionate) or afluticasone ester (e.g., the propionate).

It will be understood that the present disclosure is for the purpose ofillustration only and the invention extends to modifications, variationsand improvements thereto.

The application of which this description and claims form part may beused as a basis for priority in respect of any subsequent application.The claims of such subsequent application may be directed to any featureor combination of features described therein. They may take the form ofproduct, method or use claims and may include, by way of example andwithout limitation, one or more of the following claims:

1. A metering valve comprising: a valve body defining a metering chamberhaving an inlet and an outlet; an inlet valve adapted to be reversiblyactuable from an open to a closed position located at the inlet; anoutlet valve adapted to be reversibly actuable from a dispensing to anon-dispensing position located at the outlet, wherein said outlet valveincludes an outlet valve seat adapted to be in biasable contact with anoutlet valve poppet; and a magnetic actuating mechanism which isactuable to move the outlet valve poppet out of contact with the outletvalve seat.
 2. The metering valve according to claim 1, wherein saidinlet valve includes an inlet valve seat adapted to be in biasablecontact with an inlet valve poppet.
 3. The metering valve according toclaim 2, wherein the inlet and/or outlet valve poppet includes anincompressible material, and wherein the inlet and/or outlet valve seatincludes a compressible material.
 4. The metering valve according toclaim 2, wherein the inlet and/or outlet valve poppet includes acompressible material, and wherein the inlet and/or outlet valve seatincludes an incompressible material.
 5. The metering valve according toclaim 2, wherein the inlet valve poppet is in the form of a ball, amushroom, a cone, a disc or a plug.
 6. An aerosol container comprising ametering valve according to claim
 5. 7. The metering valve according toclaim 2, wherein the magnetic actuating mechanism is further actuable tomove the inlet valve poppet out of contact with the inlet valve seat. 8.The metering valve according to claim 7, wherein the magnetic actuatingmechanism comprises a magnetically actuable inlet mover adapted to movethe inlet valve poppet out of contact with the inlet valve seat.
 9. Anaerosol container comprising a metering valve according to claim
 8. 10.The metering valve according to claim 7, wherein the magneticallyactuable inlet valve mover includes a magnetic material or amagnetically inductive material.
 11. An aerosol container comprising ametering valve according to claim
 10. 12. The metering valve accordingto claim 7, wherein the inlet valve mover moves the inlet valve poppetout of contact with the inlet valve seat upon movement of the inletvalve mover from a first position to a second position, and wherein themagnetic actuating mechanism has an actuator element which is adapted tomagnetically interact with the inlet valve mover to move it between thefirst and second positions.
 13. An aerosol container comprising ametering valve according to claim
 12. 14. The metering valve accordingto claim 7, wherein the magnetic actuating mechanism on actuationthereof magnetically interacts with the inlet valve poppet to cause saidmovement thereof.
 15. An aerosol container comprising a metering valveaccording to claim
 14. 16. The metering valve according to claim 7,wherein the magnetic actuating mechanism has a magnet element which ismovable from a first position, in which the magnet element magneticallyinteracts with the outlet valve poppet to move the outlet valve poppetoff the outlet valve seat, to a second position, in which the magnetelement magnetically interacts with the inlet valve poppet to move theinlet valve poppet off the inlet valve seat.
 17. The metering valveaccording to claim 16 constructed and arranged such that when the outletvalve poppet is out of contact with the outlet valve seat, the inletvalve poppet is always in contact with the inlet valve seat.
 18. Anaerosol container comprising a metering valve according to claim
 17. 19.An aerosol container comprising a metering valve according to claim 16.20. The metering valve according to claim 7 constructed and arrangedsuch that when the outlet valve poppet is out of contact with the outletvalve seat, the inlet valve poppet is always in contact with the inletvalve seat.
 21. An aerosol container comprising a metering valveaccording to claim
 20. 22. An aerosol container comprising a meteringvalve according to claim
 7. 23. An aerosol container comprising ametering valve according to claim
 2. 24. The metering valve according toclaim 1, wherein the inlet valve is in the closed position and theoutlet valve is in the non-dispensing position when the metering valveis at rest.
 25. The metering valve according to claim 1, wherein theinlet valve and the outlet valve are adapted to be independentlyoperable.
 26. The metering valve according to claim 1, wherein theoutlet valve poppet is in the form of a ball, a mushroom, a cone, a discor a plug.
 27. An aerosol container comprising a metering valveaccording to claim
 26. 28. The metering valve according to claim 1,wherein said valve body additionally defines a sampling chamber, andwherein the inlet is adapted to permit flow from the sampling chamber tothe metering chamber.
 29. The metering valve according to claim 28,wherein the metering chamber is adapted to have a fixed volume.
 30. Anaerosol container comprising a metering valve according to claim
 29. 31.The metering valve according to claim 28, wherein the metering chamberis adapted to have a variable metering volume.
 32. An aerosol containercomprising a metering valve according to claim
 31. 33. An aerosolcontainer comprising a metering valve according to claim
 28. 34. Themetering valve according to claim 1, wherein the magnetic actuatingmechanism comprises a magnetically actuable outlet mover adapted to movethe outlet valve poppet out of contact with the outlet valve seat. 35.The metering valve according to claim 34, wherein the magneticallyactuable outlet valve mover includes a magnetic material or amagnetically inductive material.
 36. An aerosol container comprising ametering valve according to claim
 35. 37. The metering valve accordingto claim 34, wherein the outlet valve mover moves the outlet valvepoppet out of contact with the outlet valve seat upon movement of theoutlet valve mover from a first position to a second position, andwherein the magnetic actuating mechanism has an actuator element whichis adapted to magnetically interact with the outlet valve mover to moveit between the first and second positions.
 38. An aerosol containercomprising a metering valve according to claim
 37. 39. An aerosolcontainer comprising a metering valve according to claim
 24. 40. Themetering valve according to claim 1, wherein the magnetic actuatingmechanism on actuation thereof magnetically interacts with the outletvalve poppet to cause said movement thereof.
 41. An aerosol containercomprising a metering valve according to claim
 40. 42. An aerosolcontainer comprising a metering valve according to claim
 1. 43. Anaerosol container according to claim 42, wherein the valve body of themetering valve is not movable relative to the container.
 44. An aerosolcontainer according to claim 42, wherein the container contains asuspension of a medicament in a propellant.
 45. An aerosol containeraccording to claim 44, wherein said propellant comprises liquefiedHFA-134a, HFA-227, or carbon dioxide.
 46. An aerosol container accordingto claim 44, wherein the medicament is selected from the groupconsisting of albuterol, salmeterol, fluticasone propionate,beclomethasone dipropionate, salts or solvates thereof and any mixturesthereof.
 47. An aerosol container according to claim 42, wherein thecontainer contains a compressed gas.
 48. An aerosol container accordingto claim 47, wherein the container contains compressed air.
 49. Aninhalation device for dispensing medicament to a patient comprising: ahousing; an aerosol container, locatable within said housing, saidaerosol container comprising a metering valve that comprises a valvebody defining a metering chamber having an inlet and an outlet; an inletvalve adapted to be reversibly actuable from an open to a closedposition located at the inlet; an outlet valve adapted to be reversiblyactuable from a dispensing to a non-dispensing position located at theoutlet, wherein said outlet valve includes an outlet valve seat adaptedto be in biasable contact with an outlet valve poppet; and a magneticactuating mechanism which is actuable to move the outlet valve poppetout of contact with the outlet valve seat; and an outlet valve triggerfor triggering the movement of the outlet valve poppet out of contactwith the outlet valve seat.
 50. An inhalation device according to claim49, wherein the outlet valve trigger is triggerable in response to thebreath of a patient.
 51. An inhalation device according to claim 50,wherein the outlet valve trigger is triggerable in response to theinward breath of a patient.
 52. An inhalation device according to claim50, wherein the outlet valve trigger is triggerable at a trigger pointwhich is coupled to the end of the exhalation part of a patient's breathcycle.
 53. An inhalation device according to claim 50, wherein theoutlet valve trigger communicates with a sensor which senses the breathof a patient.
 54. An inhalation device according to claim 53, whereinsaid sensor comprises a breath-movable element which is movable inresponse to the breath of a patient.
 55. An inhalation device accordingto claim 54, wherein said breath-movable element is selected from thegroup consisting of a vane, a sail, a piston and an impeller.
 56. Aninhalation device according to claim 53, wherein said sensor comprises apressure sensor for sensing the pressure profile associated with thebreath of a patient.
 57. An inhalation device according to claim 53,wherein said sensor comprises an airflow sensor for sensing the airflowprofile associated with the breath of a patient.
 58. An inhalationdevice according to claim 53, wherein said sensor comprises atemperature sensor for sensing the temperature profile associated withthe breath of a patient.
 59. An inhalation device according to claim 53,wherein said sensor comprises a moisture sensor for sensing the moistureprofile associated with the breath of a patient.
 60. An inhalationdevice according to claim 53, wherein said sensor comprises a gas sensorfor sensing the oxygen or carbon dioxide profile associated with thebreath of a patient.
 61. An inhalation device according to claim 53,wherein said sensor comprises a piezoelectric or piezoresistive element.62. An inhalation device according to claim 49, wherein the inlet valvefurther comprises an inlet valve seat and an inlet valve poppet inbiasable contact therewith.
 63. An inhalation device according to claim62, further comprising an inlet valve trigger for triggering themovement of the inlet valve poppet out of contact with the inlet valveseat.
 64. An inhalation device according to claim 63, wherein the outletvalve trigger and the inlet valve triggers are both magnetic triggers.65. An inhalation device according to claim 64, wherein the outlet valvetrigger interacts magnetically with an outlet shuttle contacting theoutlet valve poppet and/or the inlet valve trigger interactsmagnetically with an inlet shuttle contacting the inlet valve poppet.66. An inhalation device according to claim 65, wherein the outletshuttle comprises a magnetic material.
 67. An inhalation deviceaccording to claim 65, wherein the outlet shuttle comprises a materialwhich is magnetically inductive and the outlet valve trigger comprisesan inductive element capable of inducing magnetism therein and/or theinlet shuttle comprises a material which is magnetically inductive andthe inlet valve trigger comprises an inductive element capable ofinducing magnetism therein.